The present invention relates to an electric door opener with a coil assembly which acts on a resiliently biased inner and outer armature and with a changer engaging with the inner armature for locking a door opener latch.
Such electric door openers are generally known, it being possible to distinguish between an operating current design and a closed circuit current design. Fundamentally, the function of such a door opener is based on the fact that the changer is kept in the swinging region of the door opener latch by the inner armature until the inner armature releases the latch by operation of the coil assembly, the changer then being move out of the swinging region of the door opener latch with the aid of a changer spring. In the operating current design type the inner armature is operated by supplying current to the coil assembly to oppose the bias of the armature spring, whereas a door opener of the closed circuit current design type can only be opened when power is disconnected.
Although such electric door openers operate extremely reliably and securely, in special circumstances during an impact-like force, the inner armature will be disengaged from the changer and the latch will be released.